Horsepower of the engines.

[Brian Coat]

I wonder if the most accurate data we can infer from this "what did they mean?" discussion is that people like Andy Cowell and Rob White are very experienced in press conferences!

[Wayne DR]

@ Wayne
please, who is saying that the ICE can be 40-43% efficient ?
(aren't 40-43% claims are for 'sustainable' PU efficiency ??)

70 kW Brayton cycle power ?

ok, race-sustainable power could include whatever (default) KE recovery power is available whenever driver accelerator demand is 100%
and fuel LCV is surely more than 46 MJ/kg ?

"Brayton Cycle" was my understanding of the sustainable energy mode works.
https://en.wikipedia.org/wiki/Brayton_cycle
The "combustion" process in the "Idealized Brayton cycle" diagram is the ICE (which generates power to the crank as part of the combustion process). The "work out" from the turbine shaft is the waste energy from the turbine which passed through the MGU-H to directly the MGU-K. When it is not required, it could also be used to charge the batteries (or you could run a battery charging mode).
This is a peak number when the driver is 100% on the throttle, and turbo is in its optimal window. It would vary from nothing to say 70kW, depending on Turbine/Compressor speed, the turbo efficiency island and boost pressure/mass air flow.

I never said this was a "very accurate calculation". I took a reasonable view of what some numbers could be, and did a quick and dirty calculation.

I also didn't say that 40-43% efficiency was sustainable. The numbers were meant as an absolute maximum (one point on a power curve). Similar to a "Dyno Day" pissing contest, where everyone is looking at a single number (and don't care about drivability).

Is 43% efficiency achievable on the ICE? Who knows. Both Merc and Renault claimed "over 40% thermal efficiency" last year, and 43% is over 40%. My LCV for the fuel may be low, so they could balance...

My thought was that all of the PU components have a "sweet spot", volumetric efficiency of the ICE, efficiency of the turbine, efficiency of the compressor, etc. If you can tune your PU design to line up a few of these "sweet spots", you could make big power. Would it be driveable? Who knows.

Happy to take comment on what the numbers should be...

[Edis]

I think some sources have been more explicit with terms like "self sustaining mode" which indicates (to me at least) a mode where the ICE can be run continuously without any inputs other than the 100kg/hr of fuel. The term "BTE" is only applicable to heat engines since it describes the rate of conversion of heat energy to mechanical work.

Add to this, the knowledge that 37% is available from the showroom floor (Prius with no compounding - 40+% coming soon) and it becomes obvious (to me at least) that the 40+% BTE claim is the ICE (piston engine plus turbine surplus) at continuous full power.

The "above 40%" would include power from the MGU-H, the ICE alone is probably a few points below 40%. Cosworth have publicly revealed the results of some engine simulations they did for these V6 engines, and while I can't remember the exact numbers they were in this range. About 730 hp in charge sustaining mode or something like that I believe was claimed.

[Tommy Cookers]

@ Wayne DR
sincerely,
seeing that you are 'happy to take comment on what the numbers should be' ......

the universal view seems % efficiencies quoted refer to what I called PU power (ie crankshaft power + exhaust-recovered power)
so your power figures imo seem to have counted the exhaust-recovered power twice so are optimistic by eg 70 kW

the exhaust-recovered power may well be 70 kW, but fwiw I suggest it's more blowdown recovery than Brayton
iirc gg calculated 46 kW Brayton power (based on imo rather optimistic assumptions)
blowdown because exhaust pressure/KE 'pulses' are being conserved (as far as possible) by exhaust system design
not dissipated by exhaust system design

[gruntguru]

So with 48 MJ/kg fuel and 43% BTE, the ICE would have 765 hp continuous. I think that is entirely possible.

[Edis]

So with 48 MJ/kg fuel and 43% BTE, the ICE would have 765 hp continuous. I think that is entirely possible.

48 MJ/kg is probably a bit high for a liquid hydrocarbon-based fuel. Hydrocarbons in this range are typically gases.

[Tommy Cookers]

large quantities of so-called hydrocarbon gases are in naturally in crude oil (ie dissolved in it)
for road car fuel they are removed, simply because they are more valuable as gas
in principle such 'gas' would not be removed, and some more could even be added for F1 purposes

btw - there's over 20000 known ingredients of crude oil, and about 1200 known ingredients of gasoline
most of these haven't had their octane number or LCV determined
octane number is not well predictable, and some of the unusually high LCVs are not predictable with certainty

people, please feel free to believe that Mercedes etc haven't got 48 MJ/kg fuel
though F1 is not limited to low-hanging fruit even by the rules for fuel
(iirc you can buy 47 MJ at a normal race gas price, when I last posted it anyway)
EDIT - NOTE TO SELF - 47 MJ is UCV, so LCV is about 44 MJ

[stevesingo]

It is my understanding from a chance conversation with a projoect leader working for the company who supplies fuel to a leading F1 team, that the fuel is entirely synthetic.

[Edis]

large quantities of so-called hydrocarbon gases are in naturally in crude oil (ie dissolved in it)
for road car fuel they are removed, simply because they are more valuable as gas
in principle such 'gas' would not be removed, and some more could even be added for F1 purposes

btw - there's over 20000 known ingredients of crude oil, and about 12000 known ingredients of gasoline
most of these haven't had their octane number or LCV determined
octane number is not well predictable, and some of the unusually high LCVs are not predictable with certainty

people, please feel free to believe that Mercedes etc haven't got 48 MJ/kg fuel
though F1 is not limited to low-hanging fruit even by the rules for fuel
(iirc you can buy 47 MJ at a normal race gas price, when I last posted it anyway)

Normally these gases are added to the fuel in order to adjust the vapor pressure, less of these gases lower the vapor pressure and more increases it. Still, even most gases don't reach 48 MJ/kg, and those who do typically have very low boiling points like methane (MJ/kg) or acetylene (48,1 MJ/kg). 45-46 MJ/kg is probably more realistic.

Boranes have been used in the past for high energy fuels, but they are hardly allowed in F1 today.

[chip engineer]

large quantities of so-called hydrocarbon gases are in naturally in crude oil (ie dissolved in it)
for road car fuel they are removed, simply because they are more valuable as gas
in principle such 'gas' would not be removed, and some more could even be added for F1 purposes

btw - there's over 20000 known ingredients of crude oil, and about 12000 known ingredients of gasoline
most of these haven't had their octane number or LCV determined
octane number is not well predictable, and some of the unusually high LCVs are not predictable with certainty

people, please feel free to believe that Mercedes etc haven't got 48 MJ/kg fuel
though F1 is not limited to low-hanging fruit even by the rules for fuel
(iirc you can buy 47 MJ at a normal race gas price, when I last posted it anyway)

Normally these gases are added to the fuel in order to adjust the vapor pressure, less of these gases lower the vapor pressure and more increases it. Still, even most gases don't reach 48 MJ/kg, and those who do typically have very low boiling points like methane (MJ/kg) or acetylene (48,1 MJ/kg). 45-46 MJ/kg is probably more realistic.

Boranes have been used in the past for high energy fuels, but they are hardly allowed in F1 today.

The F1 regulation that limits minimum vapor pressure (DVPE) of the fuel to 45 kPa states:
19.3 Properties :
The only fuel permitted is petrol having the following characteristics :
...
DVPE kPa 45 60(1) EN13016-1

seems to me to effectively limit the fuel to have almost no alkanes lighter than pentane.
So very little methane, ethane, propane, or butane could be used.
It is not clear to me how to get more than 46 MJ/kg.

[toraabe]

regarding 1000 hp plus this is how an old Escort MK1 behaves with 1000 hp plus enjoy

https://www.youtube.com/watch?v=qsBOUJ5MQrI

[gruntguru]

Not much to enjoy there. 1000hp available - perhaps 500 useable.

[autogyro]

Not much to enjoy there. 1000hp available - perhaps 500 useable.

Having built and driven both Rally Cosworth Escorts and built Pinto engines for two oval circuit world championship cars.
I will not say a great deal about 1000 bhp from the pinto engine and its 90 degree stove pipe porting and heavy valve gear.
I love the way the rear end gently dips on the rolling road in the video.
We had to import a hub dyno from New Zealand to measure figures above 700 bhp with power trains in the cars.
Usually we would calculate subtracted losses based on our bench dyno figures to arrive at in car figures.
During our dyno developments we offered a hub dyno to Macca for use in the F1 paddock.
The FIA had turned down rolling roads as they were too inaccurate above about 600 bhp.
Unfortunately because of cost issues (sic) the FIA preferred to believe the engine manufacturers/big car makers.
And so the spec series of F1 continued to develop.

[Sixbarboost]

I still wonder what effency you can expect from a modern ICE, above 40%?

[gruntguru]

Current SI engines (wide operating range) 30 - 35%
Current Prius (narrow operating range) 37%.
Next generation Prius engine, 40+%.
Current Mercedes F1 40++%.